Traditional machine tools, e.g., mill machines that include drill machines, are typically large, bulky and rigid that are very expensive. Current articulated robots, e.g., from KUKA, are repeatable to about 0.004 inches (0.1 mm). Proper calibration in a Euclidian space can add as little as 0.001 inches to overall accuracy giving a reasonable unloaded accuracy of 0.005 inch without any milling (or drilling) load. Today, that calibration would normally be accomplished with the aid of an optical tool such as made by Faro or Lieca. Clearly if the workspace is large, as contemplated here, the space is typically temperature controlled, although it is likely that once again, computed compensation can be used to maintain accuracy in the face of modest temperature changes.
Desirable is a robotic machine built with linear X,Y,Z axis having better repeatability of current machine tools without deflections caused by milling (or drilling) forces.